Results for "R. Farinelli"

total 131084took 0.15s
On the stability of the thermal Comptonization index in neutron star low-mass X-ray binaries in their different spectral statesSep 06 2010Most of the spectra of neutron star low mass X-ray binaries (NS LMXBs), being them persistent or transient, are characterized by the presence of a strong thermal Comptonization bump, thought to originate in the transition layer (TL) between the accretion ... More
Two Models of Stochastic Loss Given DefaultMay 24 2012May 25 2012We propose two structural models for stochastic losses given default which allow to model the credit losses of a portfolio of defaultable financial instruments. The credit losses are integrated into a structural model of default events accounting for ... More
The Black-Scholes Equation in Presence of ArbitrageApr 17 2019Jun 26 2019We apply Geometric Arbitrage Theory to obtain results in Mathematical Finance, which do not need stochastic differential geometry in their formulation. First, for a generic market dynamics given by a multidimensional It\^o's process we specify and prove ... More
The Black-Scholes Equation in Presence of ArbitrageApr 17 2019Jun 19 2019We apply Geometric Arbitrage Theory to obtain results in Mathematical Finance, which do not need stochastic differential geometry in their formulation. First, for a generic market dynamics given by a multidimensional It\^o's process we specify and prove ... More
Comptonization in ultra-strong magnetic fields: numerical solution of the radiative transfer problemDec 09 2013We consider the radiative transfer problem in a plane-parallel slab of thermal electrons in the presence of an overcritical magnetic field. Under such conditions, the magnetic field behaves as a birefringent medium for the propagating photons, and the ... More
Gauge Invariance, Geometry and ArbitrageAug 21 2009In this work, we identify the most general measure of arbitrage for any market model governed by It\^o processes. We show that our arbitrage measure is invariant under changes of num\'{e}raire and equivalent probability. Moreover, such measure has a geometrical ... More
The hard X-ray tails in neutron star low mass X-ray binaries: BeppoSAX observations and possible theoretical explanation of the GX 17+2 caseFeb 23 2007We report results of a new spectral analysis of two BeppoSAX observations of the Z source GX 17+2. In one of the two observations the source exhibits a powerlaw-like hard (> 30 keV) X-ray tail which was described in a previous work by a hybrid Comptonization ... More
The X-ray spectral evolution of Cyg X-2 in the framework of bulk ComptonizationFeb 02 2009We used the newly developed thermal plus bulk Comptonization model comptb to investigate the spectral evolution of the neutron star LMXB Cyg X-2 along its Z-track. We selected a single source in order to trace in a quantitative way the evolution of the ... More
Wide band observations of the X-ray burster GS 1826-238Nov 02 2009GS 1826-238 is a well-studied X-ray bursting neutron star in a low mass binary system. Thermal Comptonisation by a hot electron cloud is a widely accepted mechanism accounting for its high energy emission, while the nature of most of its soft X-ray output ... More
A new model for the X-ray continuum of the magnetized accreting pulsarsFeb 13 2016Accreting highly magnetized pulsars in binary systems are among the brightest X-ray emitters in our Galaxy. Although a number of high statistical quality broad-band (0.1-100 keV) X-ray observations are available, the spectral energy distribution of these ... More
A new Comptonization model for low-magnetized accreting neutron stars in low mass X-ray binariesFeb 19 2008We developed a new model for the X-ray spectral fitting \xspec package which takes into account the effects of both thermal and dynamical (i.e. bulk) Comptonization. The model consists of two components: one is the direct blackbody-like emission due to ... More
Numerical solutions of the modified Lane-Emden equation in f(R)-gravityNov 12 2013The modified Lane-Emden equation for stellar hydrostatic equilibrium in f(R)-gravity is numerically solved by using an iterative procedure. Such an integro-differential equation can be obtained in the weak field limit approximation of f(R)-gravity by ... More
Numerical solution of the radiative transfer equation: X-ray spectral formation from cylindrical accretion onto a magnetized neutron starNov 29 2011Predicting the emerging X-ray spectra in several astrophysical objects is of great importance, in particular when the observational data are compared with theoretical models. To this aim, we have developed an algorithm solving the radiative transfer equation ... More
Spectral evolution of bright NS LMXBsJan 22 2010Theoretical and observational support suggests that the spectral evolution of neutron-star LMXBs, including transient hard X-ray tails, may be explained by the interplay between thermal and bulk motion Comptonization. In this framework, we developed a ... More
Credit Risk in a Geometric Arbitrage PerspectiveJun 26 2014Jul 26 2015Geometric Arbitrage Theory, where a generic market is modelled with a principal fibre bundle and arbitrage corresponds to its curvature, is applied to credit markets to model default risk and recovery, leading to closed form no arbitrage characterizations ... More
Four Dimensional Quantum Yang-Mills Theory and Mass GapJun 16 2014Apr 18 2019A quantization procedure for the Yang-Mills equations for the Minkowski space $\mathbf{R}^{1,3}$ is carried out in such a way that field maps satisfying Wightman's axioms of Constructive Quantum Field Theory can be obtained. Moreover, the spectrum of ... More
Geometric Arbitrage Theory and Market DynamicsOct 09 2009Jul 18 2015We have embedded the classical theory of stochastic finance into a differential geometric framework called Geometric Arbitrage Theory and show that it is possible to: --Write arbitrage as curvature of a principal fibre bundle. --Parameterize arbitrage ... More
Four Dimensional Quantum Yang-Mills Theory and Mass GapJun 16 2014Jun 08 2016A quantization procedure for the Yang-Mills equations for the Minkowski space $\mathbf{R}^{1,3}$ is carried out in such a way that field maps satisfying Wightman's axioms of Constructive Quantum Field Theory can be obtained. Moreover, the spectrum of ... More
Conjugacy classes of diffeomorphisms of the interval in C1-regularityAug 23 2012In this paper we consider the conjugacy classes of diffeomorphisms of the interval, endowed with the $C^1$-topology. We present several results in the spirit of the one below : Given two diffeomorphisms $f,g$ of the interval $[0;1]$ without hyperbolic ... More
Research and development in cylindrical triple-GEM detector with $μ$TPC readout for the BESIII experimentApr 13 2019The third generation of the Beijing Electron Spectrometer, BESIII, is an apparatus for high energy physics research. The hunting of new particles and the measurement of their properties or the research of rare processes are sought to understand if the ... More
Geometric Arbitrage and Spectral TheorySep 02 2015Geometric Arbitrage Theory reformulates a generic asset model possibly allowing for arbitrage by packaging all assets and their forwards dynamics into a stochastic principal fibre bundle, with a connection whose parallel transport encodes discounting ... More
Four Dimensional Quantum Yang-Mills Theory and Mass GapJun 16 2014Mar 19 2019A quantization procedure for the Yang-Mills equations for the Minkowski space $\mathbf{R}^{1,3}$ is carried out in such a way that field maps satisfying Wightman's axioms of Constructive Quantum Field Theory can be obtained. Moreover, the spectrum of ... More
Four Dimensional Quantum Yang-Mills Theory and Mass GapJun 16 2014May 21 2019A quantization procedure for the Yang-Mills equations for the Minkowski space $\mathbf{R}^{1,3}$ is carried out in such a way that field maps satisfying Wightman axioms of Constructive Quantum Field Theory can be obtained. Moreover, by removing the ultra ... More
RX J0440.9+4431: a persistent Be/X-ray binary in outburstMar 28 2013The persistent Be/X-ray binary RX J0440.9+4431 flared in 2010 and 2011 and has been followed by various X-ray facilities Swift, RXTE, XMM-Newton, and INTEGRAL. We studied the source timing and spectral properties as a function of its X-ray luminosity ... More
The X-ray spectrum of the bursting atoll source 4U~1728-34 observed with INTEGRALJul 14 2006We present for the first time a study of the 3-200 keV broad band spectra of the bursting atoll source 4U 1728-34 (GX 354-0) along its hardness intensity diagram. The analysis was done using the INTEGRAL public and Galactic Center deep exposure data ranging ... More
The discovery of hard X-ray emission in the persistent flux of the Rapid BursterJul 16 2004We report the first detection with INTEGRAL of persistent hard X-ray emission (20 to 100 keV) from the Rapid Burster (MXB 1730-335), and describe its full spectrum from 3 to 100 keV. The source was detected on February/March 2003 during one of its recurrent ... More
Spectral evolution of the X-ray nova XTE J1859+226 during its outburst observed by BeppoSAX and RXTENov 06 2012We report results of an extensive analysis of the X-ray nova XTE J1859+226 observed with BeppoSAX and RXTE during its 1999 outburst. We modelled the source spectrum with a multicolour blackbody-like feature plus the generic Comptonization model BMC which ... More
Swift observations of two supergiant fast X-ray transient prototypes in outburstMay 31 2012We report on the results from observations of the most recent outbursts of XTE J1739-302 and IGR J17544-2619, which are considered to be the prototypes of the supergiant fast X-ray transient (SFXT) class. They triggered the Swift/BAT on 2011 February ... More
Hydroassets Portfolio Management for Intraday Electricity Trading from a Discrete Time Stochastic Optimization PerspectiveAug 21 2015Aug 24 2017Hydro storage system optimization is becoming one of the most challenging tasks in Energy Finance. While currently the state-of-the-art of the commercial software in the industry implements mainly linear models, we would like to introduce risk aversion ... More
Can You hear the Shape of a Market? Geometric Arbitrage and Spectral TheorySep 02 2015Jun 26 2019Geometric Arbitrage Theory reformulates a generic asset model possibly allowing for arbitrage by packaging all assets and their forwards dynamics into a stochastic principal fibre bundle, with a connection whose parallel transport encodes discounting ... More
The transient hard X-ray tail of GX 17+2: new BeppoSAX resultsJan 12 2005We report on results of two BeppoSAX observations of the Z source GX 17+2. In both cases the source is in the horizontal branch of the colour-intensity diagram. The persistent continuum can be fit by two-component models consisting of a blackbody plus ... More
Credit Bubbles in Arbitrage Markets: The Geometric Arbitrage Approach to Credit RiskJun 26 2014Jun 16 2019We apply Geometric Arbitrage Theory to obtain results in mathematical finance for credit markets, which do not need stochastic differential geometry in their formulation. We obtain closed form equations involving default intensities and loss given defaults ... More
Hydroassets Portfolio Management for Intraday Electricity Trading in a Discrete Time Stochastic Optimization PerspectiveAug 21 2015Jul 19 2016Hydro storage system optimization is becoming one of the most challenging task in Energy Finance. Following the Blomvall and Lindberg (2002) interior point model, we set up a stochastic multiperiod optimization procedure by means of a "bushy" recombining ... More
A QUBO Model for Gaussian Process Variance ReductionJan 30 2019Gaussian Processes are used in many applications to model spatial phenomena. Within this context, a key issue is to decide the set of locations where to take measurements so as to obtain a better approximation of the underlying function. Current state ... More
Can You hear the Shape of a Market? Geometric Arbitrage and Spectral TheorySep 02 2015Jun 11 2019Geometric Arbitrage Theory reformulates a generic asset model possibly allowing for arbitrage by packaging all assets and their forwards dynamics into a stochastic principal fibre bundle, with a connection whose parallel transport encodes discounting ... More
Centralizers of $C^1$-contractions of the half lineDec 28 2013A subgroup $G\subset Diff^1_+([0,1])$ is $C^1$-close to the identity if there is a sequence $h_n\in Diff^1_+([0,1])$ such that the conjugates $h_n g h_n^{-1}$ tend to the identity for the $C^1$-topology, for every $g\in G$. This is equivalent to the fact ... More
The Black-Scholes Equation in Presence of ArbitrageApr 17 2019We apply Geometric Arbitrage Theory to obtain results in Mathematical Finance, which do not need stochastic differential geometry in their formulation. First, for a generic market dynamics given by a multidimensional It\^o's process we specify and prove ... More
When Risks and Uncertainties Collide: Mathematical Finance for Arbitrage Markets in a Quantum Mechanical ViewJun 15 2019Geometric Arbitrage Theory reformulates a generic asset model possibly allowing for arbitrage by packaging all assets and their forwards dynamics into a stochastic principal fibre bundle, with a connection whose parallel transport encodes discounting ... More
On the Spectral Evolution of Cygnus X-2 along its Color-Color DiagramFeb 15 2002We report on the results of a broad band (0.1-200 keV) spectral study of Cyg X-2 using two BeppoSAX observations taken in 1996 and 1997, respectively, for a total effective on-source time of ~100 ks. The color-color (CD) and hardness-intensity (HID) diagrams ... More
Cooperative Queuing Policies for Effective Human-Multi-Robot InteractionJun 19 2018We consider multi-robot applications, where a team of robots can ask for the intervention of a human operator to handle difficult situations. As the number of requests grows, team members will have to wait for the operator attention, hence the operator ... More
Spectral evolution of bright NS LMXBs with INTEGRAL: an application of the thermal plus bulk Comptonization modelDec 14 2009The aim of this work is to investigate in a physical and quantitative way the spectral evolution of bright Neutron Star Low-Mass X-ray Binaries (NS LMXBs), with special regard to the transient hard X-ray tails. We analyzed INTEGRAL data for five sources ... More
The Swift Supergiant Fast X-ray Transients Project: a review, new results, and future perspectivesJul 26 2013We present a review of the Supergiant Fast X-ray Transients (SFXT) Project, a systematic investigation of the properties of SFXTs with a strategy that combines Swift monitoring programs with outburst follow-up observations. This strategy has quickly tripled ... More
Supergiant Fast X-ray Transients with Swift: spectroscopic and temporal propertiesSep 30 2012Supergiant fast X-ray transients (SFXTs) are a class of high-mass X-ray binaries with possible counterparts in the high energy gamma rays. The Swift SFXT Project has conducted a systematic investigation of the properties of SFTXs on timescales ranging ... More
Average hard X-ray emission from NS LMXBs: Observational evidence of different spectral states in NS LMXBsJul 26 2006Oct 02 2006We studied and compared the long-term average hard X-ray (>20keV) spectra of a sample of twelve bright low-mass X-ray binaries hosting a neutron star (NS). Our sample comprises the six well studied Galactic Z sources and six Atoll sources, four of which ... More
Hunting the nature of IGR J17497-2821 with X-ray and NIR observationsNov 10 2006Feb 01 2007We report on a Chandra grating observation of the recently discovered hard X-ray transient IGR J17497-2821. The observation took place about two weeks after the source discovery at a flux level of about 20 mCrab in the 0.8-8 keV range. We extracted the ... More
BeppoSAX observations of two unclassified LMXBs: X1543-624 and X1556-605Jan 22 2003Mar 26 2003Observations of two unclassified Low Mass X-ray Binaries, X1543-624 and X1556-605, are presented. In the 2-10 keV band the first of the two sources is a factor two stronger than the other. Both sources do not show X-ray bursts, dips or eclipses in their ... More
INTEGRAL spectroscopy of the accreting millisecond pulsar XTE J1807-294 in outburstMar 14 2005Mar 18 2005The fourth transient accreting millisecond pulsar XTE J1807-294 was observed during its February/March 2003 outburst by INTEGRAL, partly simultaneously with the XMM-Newton and RXTE satellites. We present here the first study of the 0.5-200 keV broad-band ... More
A Hard X-ray View on Scorpius X-1 with INTEGRAL: non-Thermal Emission ?Aug 16 2006We present here simultaneous INTEGRAL/RXTE observations of Sco X-1, and in particular a study of the hard X-ray emission of the source and its correlation with the position in the Z-track of the X-ray color-color diagram. We find that the hard X-ray (above ... More
High-resolution tracking in a GEM-Emulsion detectorMay 18 2017Aug 10 2017SHiP (Search for Hidden Particles) is a beam dump experiment proposed at the CERN SPS aiming at the observation of long lived particles very weakly coupled with ordinary matter mostly produced in the decay of charmed hadrons. The beam dump facility of ... More
Simultaneous multiwavelength observations of the Low/Hard State of the X-ray transient source SWIFT J1753.5-0127Dec 20 2006We report the results of simultaneous multiwavelength observations of the X-ray transient source SWIFT J1753.5-0127 performed with INTEGRAL, RXTE, NTT, REM and VLA on 2005 August 10-12. The source, which underwent an X-ray outburst since 2005 May 30, ... More
The dark burst 010214 with BeppoSAX: possible variable absorption and jet X-ray emissionFeb 01 2003We report on the prompt and afterglow emission observations of the dark burst GRB010214 with BeppoSAX. The prompt emission shows possible evidence of variable absorption from N_H = 3.0^{+5.1}_{-2.0} x 10^23 cm-2 in the first 6 s of the event to a value ... More
1E 1740.7-2942: temporal and spectral evolution from INTEGRAL and RXTE observationsNov 18 2004Nov 19 2004We present results of the monitoring of the black hole candidate 1E 1740.7-2942 with INTEGRAL, in combination with simultaneous observations by RXTE. We concentrate on broad-band spectra from INTEGRAL/IBIS and RXTE/PCA instruments. During our observations, ... More
Serpens X-1 observed by INTEGRALMay 14 2004May 21 2004Here we report results of an INTEGRAL-AO1 observation of the X-ray burst and atoll source Ser X-1 performed in May 2003. The object was observed for a total on-source time of 400 ks but nearly 8 degrees off-axis due to its amalgamation with an observation ... More
Performance of the LHCb Vertex LocatorMay 30 2014Sep 10 2014The Vertex Locator (VELO) is a silicon microstrip detector that surrounds the proton-proton interaction region in the LHCb experiment. The performance of the detector during the first years of its physics operation is reviewed. The system is operated ... More
High-energy observations of the state transition of the X-ray nova and black hole candidate XTE J1720-318Jul 15 2004Jul 16 2004We report the results of extensive high-energy observations of the X-ray transient and black hole candidate XTE J1720-318 performed with INTEGRAL, XMM-Newton and RXTE. The source, which underwent an X-ray outburst in 2003 January, was observed in February ... More
Scientific prospects in soft gamma-ray astronomy enabled by the LAUE projectOct 02 2013Jan 02 2014This paper summarizes the development of a successful project, LAUE, supported by the Italian Space Agency (ASI) and devoted to the development of long focal length (up to 100 m) Laue lenses for hard X--/soft gamma--ray astronomy (80-600 keV). The apparatus ... More
The Mass-Radius relation for Neutron Stars in $f(R)$ gravitySep 10 2015Nov 30 2015We discuss the Mass -Radius diagram for static neutron star models obtained by the numerical solution of modified Tolman-Oppenheimer-Volkoff equations in $f(R)$ gravity where the Lagrangians $f(R)=R+\alpha R^2 (1+\gamma R)$ and $f(R)=R^{1+\epsilon }$ ... More
The INTEGRAL LMXRB Monitoring ProgrammeMay 19 2004Our collaboration is responsible for the study of a sample of 72 low mass X-ray binaries (LMXRB) using the INTEGRAL Core Programme data. In this paper we describe the monitoring programme we have started and the current variability and spectral results ... More
A new $G$-parity violating amplitude in the $J/ψ$ decay?Aug 25 2016Sep 09 2016The $J/\psi$ meson has negative $G$-parity so that, in the limit of isospin conservation, its decay into $\pi^+\pi^-$ should be purely electromagnetic. However, the measured branching fraction $\mathcal{B}(J/\psi\to\pi^+\pi^-)$ exceeds by more than 3.9 ... More
An upscattering spectral formation model for the prompt emission of Gamma-Ray BurstsApr 15 2012We propose a model for the spectral formation of Gamma Ray Burst (GRB) prompt emission, where the phenomenological Band's function is usually applied to describe the GRB prompt emission. We suggest that the GRB prompt emission is mainly a result of two ... More
A model to explain angular distributions of $J/ψ$ and $ψ(2S)$ decays into $Λ\overlineΛ$ and $Σ^0\overlineΣ^0$Sep 12 2018Nov 30 2018BESIII data show a particular angular distribution for the decay of the $J/\psi$ and $\psi(2S)$ mesons into the hyperons $\Lambda\overline{\Lambda}$ and $\Sigma^0\overline{\Sigma}^0$. More in details the angular distribution of the decay $\psi(2S) \to ... More
Performance of the micro-TPC Reconstruction for GEM Detectors at High RateMar 20 2018Gas detectors are one of the pillars of the research in fundamental physics. Since many years, a new concept of detectors, the Micro Pattern Gas Detectors, allows to overcome many of the problems of other types of commonly used detectors, as drift chambers ... More
Innovative design and construction technique for the Cylindrical GEM detector for the BESIII experimentMar 21 2018Gas detector are very light instrument used in high energy physics to measure the particle properties: position and momentum. Through high electric field is possible to use the Gas Electron Multiplier (GEM) technology to detect the particles and to exploit ... More
The Cylindrical GEM Inner Tracker of the BESIII experiment: prototype test beam resultsJun 08 2017Jul 03 2017A cylindrical GEM detector is under development, to serve as an upgraded inner tracker at the BESIII spectrometer. It will consist of three layers of cylindrically-shaped triple GEMs surrounding the interaction point. The experiment is taking data at ... More
A fast and parametric digitization for triple-GEM detectorsApr 12 2019Triple-GEM detectors are a well known technology in high energy physics. In order to have a complete understanding of their behavior, in parallel with on beam testing, a Monte Carlo code has to be developed to simulate their response to the passage of ... More
Algorithms for Graph-Constrained Coalition Formation in the Real WorldDec 13 2016Coalition formation typically involves the coming together of multiple, heterogeneous, agents to achieve both their individual and collective goals. In this paper, we focus on a special case of coalition formation known as Graph-Constrained Coalition ... More
Comptonization signatures in the prompt emission of Gamma Ray BurstsNov 08 2013Jan 02 2014We report results of a systematic study of the broad--band (2--2000 keV) time--resolved prompt emission spectra of a sample of Gamma-Ray Bursts (GRBs) detected with both the Wide Field Cameras (WFCs) aboard the BeppoSAX satellite and the BATSE experiment ... More
The new cylindrical GEM inner tracker of BESIIIMar 20 2018The Cylindrical GEM-Inner Tracker (CGEM-IT) is the upgrade of the internal tracking system of the BESIII experiment. It consists of three layers of cylindrically-shaped triple GEMs, with important innovations with respect to the existing GEM detectors, ... More
Test beam results of a Cylindrical GEM detector for the BESIII experimentMar 20 2018Gas detector are very light instrument used in high energy physics to measure the particle properties: position and momentum. Through high electric field is possible to use the Gas Electron Multiplier (GEM) technology to detect the charged particles and ... More
Was ordinary matter synthesised from mirror matter? An attempt to explain why $Ω_{Baryon} \approx 0.2Ω_{Dark}$Apr 28 2003Jun 03 2003The cosmological dust has begun to settle. A likely picture is a universe comprised (predominantly) of three components: ordinary baryons ($\Omega_B \approx 0.05$), non-baryonic dark matter ($\Omega_{Dark} \approx 0.22$) and dark energy ($\Omega_{\Lambda} ... More
How neutrino oscillations can induce an effective neutrino number of less than 3 during Big Bang NucleosynthesisJun 04 1997Ordinary-sterile neutrino oscillations can generate significant neutrino asymmetry in the early Universe. In this paper we extend this work by computing the evolution of neutrino asymmetries and light element abundances during the Big Bang Nucleosynthesis ... More
Maximal neutrino oscillation solution to the solar neutrino problemOct 17 1995We discuss a simple predictive solution to the solar neutrino problem based on maximal vacuum neutrino oscillations. The solution can be motivated by the exact parity symmetric model which predicts that the neutrino mass eigenstates are maximal mixtures ... More
A mirror world explanation for the Pioneer spacecraft anomalies?Aug 06 2001We show that the anomalous acceleration of the Pioneer 10/11 spacecraft can be explained if there is some mirror gas or mirror dust in our solar system.
The exact parity symmetric model and big bang nucleosynthesisDec 04 1996The assumption of exact, unbroken parity symmetry leads directly to a simple predictive resolution of the atmospheric and solar neutrino puzzles. This is because the existence of this symmetry implies the existence of a set of mirror neutrinos which must ... More
Test beam results with prototypes for the new Cylindrical GEM Inner Tracker of the BESIII experimentMar 20 2018A cylindrical GEM tracker is under construction in order to replace and improve the inner tracking system of the BESIII experiment. Tests with planar chamber prototypes were carried out on the H4 beam line of SPS (CERN) with muons of 150 GeV/c momentum, ... More
GRAAL: Gem Reconstruction And Analysis LibraryMay 08 2019MPGD are the new frontier in gas trackers. Among this kind of devices, theGEM chambers are widely used. The experimental signals acquired with the detector mustobviously be reconstructed and analysed. In this contribution, a new offline software to performreconstruction, ... More
Reconciling sterile neutrinos with big bang nucleosynthesisAug 10 1995Nov 08 1995We re-examine the big bang nucleosynthesis (BBN) bounds on the mixing of neutrinos with sterile species. These bounds depend on the assumption that the relic neutrino asymmetry $L_{\nu}$ is very small. We show that for $L_{\nu}$ large enough (greater ... More
Implications of mirror neutrinos for early universe cosmologyApr 15 1999The Exact Parity Model (EPM) is, in part, a theory of neutrino mass and mixing that can solve the atmospheric, solar and LSND anomalies. The central feature of the neutrino sector is three pairs of maximally mixed ordinary and mirror neutrinos. It has ... More
Generalised leptonic colourJul 05 2006Dec 06 2006It is conceivable that there is an $SU(N)_{\ell}$ `colour' gauge group for leptons, analogous to the gauged $SU(3)_q$ colour group of the quarks. The standard model emerges as the low energy effective theory when the leptonic colour is spontaneously broken. ... More
Spheroidal galactic halos and mirror dark matterJul 26 2004Mirror matter has been proposed as a dark matter candidate. It has several very attractive features, including automatic stability and darkness, the ability to mimic the broad features of cold dark matter while in the linear density perturbation regime, ... More
New and improved quark-lepton symmetric modelsMay 18 1995We show how the use of a see-saw mechanism based on a $3 \times 3$ neutrino mass matrix texture can considerably simplify Higgs sectors for quark-lepton symmetric models (and for Standard Model extensions generally). The main theory we discuss also incorporates ... More
Natural electroweak symmetry breaking in generalised mirror matter modelsOct 02 2006Nov 28 2006It has recently been pointed out that the mirror or twin Higgs model is more technically natural than the standard model, thus alleviating the ``little'' hierarchy problem. In this paper we generalise the analysis to models with an arbitrary number of ... More
Studies of neutrino asymmetries generated by ordinary-sterile neutrino oscillations in the early universe and implications for big bang nucleosynthesis boundsOct 03 1996Nov 19 1996Ordinary-sterile neutrino oscillations can generate a significant lepton number asymmetry in the early Universe. We study this phenomenon in detail. We show that the dynamics of ordinary-sterile neutrino oscillations in the early Universe can be approximately ... More
Do the SuperKamiokande atmospheric neutrino results explain electric charge quantisation?Aug 24 1998We show that the SuperKamiokande atmospheric neutrino results explain electric charge quantisation, provided that the oscillation mode is $\nu_{\mu} \to \nu_{\tau}$ and that the neutrino mass is of Majorana type.
Neutrino physics and the mirror world: how exact parity symmetry explains the solar neutrino deficit, the atmospheric neutrino anomaly and the LSND experimentMay 23 1995Nov 08 1995Evidence for $\bar \nu_{\mu} \rightarrow \bar \nu_e$ oscillations has been reported at LAMPF using the LSND detector. Further evidence for neutrino mixing comes from the solar neutrino deficit and the atmospheric neutrino anomaly. All of these anomalies ... More
Comment on "Big Bang Nucleosynthesis and Active-Sterile Neutrino Mixing: Evidence for Maximal $ν_μ\leftrightarrow ν_τ$ Mixing in Super Kamiokande?"Nov 04 1998The paper "Big Bang Nucleosynthesis and Active-Sterile Neutrino Mixing: Evidence for Maximal $\nu_\mu \leftrightarrow \nu_\tau$ Mixing in Super Kamiokande?" by X. Shi and G. M. Fuller (astro-ph/9810075) discusses the cosmological implications of the $\nu_\mu ... More
Explaining $Ω_{Baryon} \approx 0.2 Ω_{Dark}$ through the synthesis of ordinary matter from mirror matter: a more general analysisFeb 25 2004Mar 25 2004The emerging cosmological picture is of a spatially flat universe composed predominantly of three components: ordinary baryons ($\Omega_B \approx 0.05$), non-baryonic dark matter ($\Omega_{Dark} \approx 0.22$) and dark energy ($\Omega_{\Lambda} \approx ... More
The neutrino puzzle in the light of SNOApr 23 2002Jul 23 2002SNO's neutral current measurement has added a new piece to the emerging neutrino physics puzzle. Putting together the presently available experimental information, an essentially unique picture emerges: The solar neutrino anomaly is explained by nu_e ... More
A Cylindrical GEM Inner Tracker for the BESIII experiment at IHEPJul 02 2018The Beijing Electron Spectrometer III (BESIII) is a multipurpose detector that collects data provided by the collision in the Beijing Electron Positron Collider II (BEPCII), hosted at the Institute of High Energy Physics of Beijing. Since the beginning ... More
Development and Test of a uTPC Cluster Reconstruction for a Triple GEM Detector in Strong Magnetic FieldJul 14 2017Performance of triple GEM prototypes has been evaluated by means of a muon beam at the H4 line of the SPS test area at CERN. The data from two planar prototypes have been reconstructed and analyzed offline with two clusterization methods: the enter of ... More
Legendrian contact homology and topological entropySep 12 2014Apr 23 2016In this paper we study the growth rate of a version of Legendrian contact homology, which we call strip Legendrian contact homology, in 3-dimensional contact manifolds and its relation to the topological entropy of Reeb flows. We show that: if for a pair ... More
The heat-kernel and the average effective potentialMay 29 1995We discuss the definition of the average effective action in terms of the heat-kernel. As an example we examine a model describing a self-interacting scalar field, both in flat and curved background, and study the renormalization group flow of some of ... More
The renormalization group flow of the dilaton potentialDec 20 1994We consider a scalar-metric gauge theory of gravity with independent metric, connection and dilaton. The role of the dilaton is to provide the scale of all masses, via its vacuum expectation value. In this theory, we study the renormalization group flow ... More
Ordinary-derivative formulation of conformal low-spin fieldsJul 30 2007Nov 14 2011Conformal fields in flat space-time of even dimension greater than or equal to four are studied. Second-derivative formulation for spin 0,1,2 conformal bosonic fields and first-derivative formulation for spin 1/2,3/2 conformal fermionic fields are developed. ... More
Gravitational and higher-derivative interactions of massive spin 5/2 field in (A)dS spaceDec 27 2006Sep 10 2007Using on-shell gauge invariant formulation of relativistic dynamics we study interaction vertices for a massive spin 5/2 Dirac field propagating in (A)dS space of dimension greater than or equal to four. Gravitational interaction vertex for the massive ... More
CFT adapted gauge invariant formulation of arbitrary spin fields in AdS and modified de Donder gaugeAug 28 2008Jan 22 2009Using Poincare parametrization of AdS space, we study totally symmetric arbitrary spin massless fields in AdS space of dimension greater than or equal to four. CFT adapted gauge invariant formulation for such fields is developed. Gauge symmetries are ... More
CFT adapted approach to massless fermionic fields, AdS/CFT, and fermionic conformal fieldsNov 28 2013Dec 10 2013Fermionic totally symmetric arbitrary spin massless fields in AdS space of dimension greater than or equal to four are studied. Using Poincar\'e parametrization of AdS space, CFT adapted gauge invariant formulation for such fields is developed. We demonstrate ... More
The Color-Flavor Locking Phase at T \not =0$Sep 17 1999Nov 03 1999We study the color-flavor locked phase of QCD with three massless quarks at high chemical potential and small non zero temperatures. We make use of the recently introduced effective action to describe such a phase. We obtain the exact order T^2 behaviour ... More
TARCER - A Mathematica program for the reduction of two-loop propagator integralsJan 21 1998TARCER is an implementation of the recurrence algorithm of O.V. Tarasov for the reduction of two-loop propagator integrals with arbitrary masses to a small set of basis integrals. The tensor integral reduction scheme is adapted to moment integrals emerging ... More
Implications of the JHF-Kamioka neutrino oscillation experimentNov 20 2002After quickly reviewing the existing evidence for neutrino oscillations, I summarise the goals and capabilities of the JHF-Kamioka long baseline superbeam experiment. Theoretical implications of what this experiment could potentially discover are then ... More